Brushes and their manufacture



Nov. 8, 1955 E. D. PEcK ETAL BRUSHES AND THEIR MANUFACTURE Filed NOV. 3, 1951 FIGJ BRUSHES AND THEIR MANUFACTURE Elbert D. Peck, Pittsburgh, Pa., and Joseph V. Mertes and George E. Hartwell, Catonsville, Md., assignors to Pittsburgh Plate Glass Company Application November 3, 195.1, Serial N o. 254,666

Claims; (Cl. 1'5-205) This invention relates to brushes. More particularly, the invention has to do with paint brush elements.

In the present state of the brush art, 4high grade brushes adapted for applying paint 'to flat surfaces are constructed of a plurality of row 'of tapered bristles set in vulcanized rubber or other cured plastic. The bristles, set in the matrix at their fixed or butt ends, are lusually secured to a hard wood handle by means of a vmetal 'ferrule nailed through the bristle assembly and the stock of the handle. The construction of such a lconventional brush entails the use of expensive materials and it entails manual operations which must be carefully and laboriously accomplished.

An accomplished objective of our invention is the provision of a brush, the principal elements of which can be fabricated by machine, of simple and light weight construction affording economy in the process of manufacture, a high degree of efficiency in operation, and useful in extreme widths.

A further achieved objective of the invention is the provision of a finished article employing fewer bristles than heretofore and to afford a novel arrangement of the bristles within the brush 'structure resulting in improved utility of the brush.

One embodiment of our invention is more or less diagrammatically illustrated 4in the accompanying drawing wherein:

Fig. 1 is a fragmentary side elevation of a brush embodying the principles of theinvention;

Fig. 2 is a partly sectional and partly elevational view taken along the line II-II of Fig. `l showing in particular the arrangement by which the bristle elements are clamped together for attachment to a handle, Ithis figure being somewhat enlarged from the scale of Fig. l;

Fig. 3 is a fragmentary perspective view showing in detail the arrangement of the bristles and their holding elements during one stage of the manufacture of the brush;

Fig. 4 is a fragmentary sectional View taken along the line IV-IV of Fig. l showing the novel disposition of the bristles in the composite assembly; and

Fig. 5 is an elevation of a double tapered monofilament of synthetic origin, a plurality of which are used in a manner hereinafter described to form the bristle elements of the brush.

In practicing the invention -according to 'the embodiment illustrated in the drawing, we first select a mass of double-tapered synthetic fibers or filaments of suitable length, diameter and 'taper with regard to the character of bristles desired in the final product. Such bristles are robtained by known methods-from linear polyamides, cellulose triacetate, or other suitable synthetic lamentforming material. The bristles 10 are looped or doubled around an anchoring element or core 11 which is in the form of a continuous filament such as a wire, cable, cord, or the like so that the two ends .of each filament project outwardly in .nearly .the same direction. The

composite bristle lstructure thus formed :of looped Idoublci? Y United States Patent aO rice tapered fibers is held in fixed relationship in a sheet metal channel back strip generally indicated at 12 having a base or web '13 abutting the bristles adjacent their doubled portion and having planar side walls 14 inwardly inclined to provide a trapezoidal section and to constri'ct the bristles about the anchoring element 11. The bristles are thus placed under pressure and held within the channel owing to their inherent resiliency. Conveniently, the side walls of the channel element may be crimped as at 15 'to prevent the bristles slipping along the axis of the anchoring element 11 and to assist in maintaining them in the proper vertical relationship to the base and sides ofthe channel. Owing 'to the mass and resiliency 'of the bristles, they flare outwardly from 'the constricted portion of the channel as shown in Figs. 2 and '3.

`Elements 10, 11, 12, 13 and 14 can be assembled by machine if desired as a continuous strip, one suitable apparatus and method therefor being disclosed in United States Letters Patent No. 1,871,775. Such a strip is suitable for cutting in any desired length and is well adapted for use in accomplishing the purposes of our invention.

A plurality of such strips, two, for example, as illustrated in the drawing, are prepared for assembly by cutting to the desired length and pressing the side walls at each end to enclose the lfibers and `engage the anchoring element as illustrated at 16 in Fig. 4. The tips of the bristles of each strip section are trimmed obliquely atan angle of approximately 15 to the horizontal so that the bristles on one side of the strip are uniformly longer than those on 'the other side. Two or more sections of brush strip thus prepared, preferably of equal length, are arranged in side'by side relationship with the inner `side walls in flat -contact with the longest bristles of each strip on the inside, and one wall of each strip engaging the adjacent wall of the other coextensively. In so doing, the bristles of one strip at the inside of the assembly are inwardly inclined with respect to the inside bristles of the adjacent assembly. It will be evident from reference to Fig. 2 of the drawings that planes such as the median planes of 'the bristle sections 'running longitudinally of the sections and being normal to the planes of the webs or bases 13 of the channels are convergent toward the tips of the bristles. This is indicated by the broken lines X and Y in Fig. r2. Therefore, the innermost bristles converge at a junction 17 a slight distance above the base of 'the assembly. Above the junction 17 the inner bristles of each strip press against those of the other for a considerable portion of their length and thus reinforce each other. When assembled, the outer wall of each individual channel converges toward 'the other, but the outermost bristles in yeach corresponding element are almost parallel to, or flare slightly outward from, those outermost in the other as shown in Fig. 3. The tip of the composite brush 'at this stage of manufacture has a chisel shape. i

The pair of brush elements thus positioned together are fixed yin position by means of a split saddle type strap 20 having oppositely disposed inwardly convergent resilient bracket arms '21 providing a channel-like clamp surrounding and engaging the channel sections at their out-er extremities as shown in Fig. v2. The base of each lbracket arm 21 is arranged to engage the base or web 13 of one of the channels of the brush element 1'2 and each has .a lip 25 reaching over 'the outside wall of the corresponding element i2 and retaining the brush strip in engagement. Portions A21a of the arms 21 are convergently downwardly inclined at angles corresponding to the inclination of the base or web portions 13 when the inner side walls 14 are in contact with each other. It will thus be evident that the outer of the side walls `14 of the -channelsand the base or web portions 13 .are'posi-- tively engaged by portions 321 'and 21a "of'thestraps 20,'

with the inner side walls positively pressed together and by reason of the trapezoidal section of the channel strips 12, they are positively keyed in the saddle or by clamping member by a wedging action, much as are the voussoirs in a masonry arch.

In assembly, the two arms 21 of the saddle strap or channel-like clamp are first engaged with their lips 25 against the upper extremity of the strips and they are then brought together at their base and fastened under pressure by spot welding or other means 22. The construction and dimensions of the strap elements are such that each channel wall 14 is held in tension between the lip and the base of the arm 21. The handle 23 is then secured to a socket portion 20a of the strap 20 by any suitable fastening means such as rivets 26.

The convergent arms 21 and the divergent sections 21a connecting the arms to the handle, in section, provide a fork-like structure in which said divergent portions 21a resemble the branches of a Y with the handle as the stem.

To complete the manufacture of the brush, the angular chisel tip of the brushing element thus formed as illustrated in Fig. 3 is rounded off. We prefer to accomplish this in two steps. At rst, the tip is trimmed in a cutter to the shape shown in cross section at Fig. 2. Then the tip is sanded by means of a controlled action which serves the purpose of imparting a velvet-like fineness to the tip of the brush, much desired in the art.

Brushes manufactured according to the invention as described have been demonstrated to have unusual paint pick-up and delivery characteristics. Without intending to be limited thereby, we attribute this to the fact that the inner bristles of each section press against the inner bristles of the opposite section forming a dense mass at the center which minimizes the tendency for accumulation of paint at the center of the brush and obviates leakmg.

While any number of individual brush strip elements may be assembled together according to the teachings of our invention to provide a composite brush, we have made the remarkable discovery that fewer bristles are required in all in our novel brush than in a brush of similar width made in accordance with prior art teachings. Thus, for example, a brush of our invention made with two individual strip elements in 7-inch width will operate more eciently than a prior art brush of the same width and quantity of bristle. Undoubtedly, this is at least partially attributable to the action of the bristles in reinforcing each other against bending by virtue of their converging relationship at the center of the composite structure.

A typical brush made in accordance with our invention with two brush strips of 7inch width and 3% inch bristle length above the channels weighs approximately l0 ounces as compared to a brush of the prior art, the bristles of which are set in rubber, with the same width and bristle length weighing 14 ounces.

Our novel construction obviates the necessity for a heavy rubber or plastic setting for the bristles and obviates the necessity for a deep ferrule. Consequently, the actual working surface is brought closer to the handle than is possible with prior art structures. Thus, for a given width of brush, good balance can be obtained with a shorter handle and lighter over-all weight than was heretofore attainable.

Although the invention has been described with particular reference to the specilic embodiment illustrated in the drawings, it will be apparent to those skilled in the art that the brushes and the methods of their manufacture described herein may be modified in various ways within the purview of the invention without departure from the scope or spirit of the appended claims.

We claim:

1. A brush comprising a handle and a saddle attached to an end thereof, said handle and saddle in section forming a two-pronged fork of which, the sides of the saddle constitute prongs convergent toward their tips and the cross portions connecting the prongs to the handle comprise sections diverging as Y-like branches away from the handle as a stem, brush strip sections comprising channels having side walls and webs connecting said side walls and double ended bristles disposed in the channels and being locked in position by cores extending longitudinally of the channels, the channels being disposed in the saddles with the webs thereof seated upon said divergent cross portions, the side walls being convergent with respect to each toward the tips of the prongs of said fork and a side wall of the channel of one strip being pressed against the adjacent side wall of the other and the outer side walls being clamped by the prongs with the plane normal to the web of the channel of one of the strips convergent towards that of the other and the tip portions of the bristles upon one face of each strip being pressed against the corresponding portions in the adjacent bristles of the other strip to form a brush.

2. A brush comprising a handle and a saddle attached to an end thereof, said handle and saddle in section forming a two-pronged fork of which the sides of the saddle constitute prongs convergent toward their tips and the cross portions connecting the prongs to the handle comprise sections diverging as Y-like branches away from the handle as a stem, brush strip sections comprising channels having side walls and webs connecting said side walls and double ended bristles disposed in the channels and being locked in position by cores extending longitudinally of the channels, the channels being disposed in the saddles with the webs thereof seated upon said divergent cross portions, the side walls being convergent with respect to each other toward the tips of the prongs of said fork and a side wall of the channel of one strip being pressed against the adjacent side wall of the other and the outer side walls being clamped by the prongs with the plane normal to the web of the channel of one of the strips convergent toward that of the other and the tip portions of the bristles upon one face of each strip being pressed against the corresponding portions in the adjacent bristles of the other strip to form a brush, the tip portions of the prongs being bent over as lips engaging the contiguous side walls of the channels to press the webs of said channels against said cross portions.

3. A brush assembly comprising a pair of metallic plates having portions secured together in superposed relationship with respect to each other, said portions further having opposed indentations formed therein at one end thereof forming a handle socket, a handle disposed in the socket, the opposite ends of the plates being outwardly divergently bent to provide a saddle of fork-like section and comprising cross portions, divergent as the branches of a Y and having prongs convergent toward their tips upon the ends thereof, brush strips comprising channels each channel comprising a web forming a base, side walls convergent from the webs toward the tips of the prongs, the webs of the channels being seated upon the cross portions, contiguous side walls of the channels being pressed together and the outer side walls of the channels being engaged by and gripped by the convergent prongs, double ended bristles disposed in the channels, cores locking the bristles in the channels and the planes extending longitudinally of the channels and being normal to the Webs being convergent toward the tips of the bristles, bristles upon contiguous sides of the strips converging and being pressed against each other.

4. A brush assembly comprising a pair of metallic plates having portions secured together in superposed relationship with respect to each other, said portions further having indentations formed therein at one end thereof forming a socket, a handle disposed in the socket, the opposite ends of the plates being bent to provide a saddle of fork-like section and comprising cross portions, divergent from the handle as the branches of a Y and having fork-like prongs upon the ends thereof, convergent toward their tips, brush strips comprising channels, each channel comprising a web forming a base, side walls convergent from the webs, the webs of the channels being seated upon the cross portions, contiguous side walls of the channels being pressed together and the outer side walls of the channels being engaged by and gripped by the convergent prongs, double ended bristles disposed in the channels, cores locking the bristles in the channels and the planes extending longitudinally of the channels and normally to the webs being convergent toward the tips of the bristles, bristles upon contiguous sides of the strips converge and being pressed against each other, the tip portions of the prongs being bent over as lips engaging the contiguous side walls of the channels to press the Webs of said channels against said cross portions.

5. A brush assembly suitable for spreading paint comprising a saddle, upon an end of a handle, said saddle forming a slot and having seating bottom portions divergent outwardly with respect to each other as the branches of a Y with the handle as the stem of the Y and side portions at the ends of the branches of the Y convergent toward the tip of the brush and brush strips forming a bristle portion for said brush disposed in the saddle and comprising channels having side walls convergent toward the tip of said bristle portion and interconnecting Webs between the side walls and bristles secured in the channels, the Webs being seated upon said seating portions of the saddle, the contiguous side walls being pressed together and the outer side walls of the channels being engaged by the convergent side portions of the saddle to clamp the channels in place in said saddle, planes extending longitudinally of the channels and normally to the webs being convergent toward the tips of the bristles and bristles in contiguous sides of the strips being pressed together.

References Cited in the le of this patent UNITED STATES PATENTS 60,688 Carroll Jan. 1, 1867 122,421 White Jan. 2, 1872 2,293,302 Morck Aug. 18, 1942 2,367,650 Rowland Ian. 16, 1945 2,408,719 HauX Oct. 1, 1946 2,509,013 Parks May 23, 1950 2,511,004 Peterson June 13, 1950 2,561,025 Le Febvre July 17, 1951 

